This invention relates to a method of preparing compounds that are useful intermediates in the production of compounds which have utility as plant growth regulators, weed killers, defoliating agents and agricultural chemicals.
In modern day agriculture, chemicals are used extensively for weed and plant control, and as defoliating agents. Many different types of chemical agents are being used, having varying degrees of herbicidal activity. While the chemicals currently used are in general adequate, they are sufficiently expensive that expense is a significant factor in their use. Therefore, new compounds and inexpensive methods for producing such compounds are constantly being sought.
In addition, while many compounds presently on the market are effective against certain species of weeds, they are ineffective against others. Thus new herbicides which have broad spectrum effectiveness against a wide variety of weeds are continually being sought.
It has been discovered that certain substituted-pyrido[3,2-d]pyrimidine-2,4(1H,3H)-diones, some analogous [2,3-d], [3,4-d] and [4,3 -d] dione compounds, and certain lumazines have unexpectedly high levels of herbicidal activity.
The instant invention is directed to a method of making intermediate compounds which are used in the production of the aforementioned pyridopyrimidine diones and lumazines.
It is an object of this invention to provide a method for making intermediate compounds which are useful in the production of compounds which are effective plant growth regulators and weed killers.
It is a further object of this invention to provide a method of making compounds which are themselves weed killers.
It is a further object of this invention to provide a method of making N-monosubstituted-2,3- and 3,4-pyridinedicarboxamides, and 2,3-pyrazinedicarboxamides, and the compounds made by such method.
Other objects and benefits of this invention will be apparent from the following disclosure.